Easy opening container wall

ABSTRACT

An easy opening container wall including a main score line in the container wall defining a panel removable therefrom and a tab connected to the panel to initiate severance of the panel. A plurality of generally radially extending secondary score lines are formed in the panel and sections of the panel are preferably axially offset relative to each other.

United States Patent Fraze et al.

[ 1 Feb. 22, 1972 [54] EASY OPENING CONTAINER WALL [72] Inventors: Erma]C. Fraze, 355 West Stroop Road,

Dayton, Ohio 45429; Franklin C. Eickenhorst, Mason, Ohio [73] Assignee:Ermal C. Fraze, Dayton, Ohio a part interest 22 Filed: Nov. 4, 1969 21Appl.No.: 873,889

[52] US. Cl ..220/54 [5i] Int. Cl ..B65d 17/24 [58] Field of Search..220/54, 27, 48

[56] References Cited UNITED STATES PATENTS 3,485,410 I 2/1969 Boik..220/54 OTHER PUBLICATIONS The O. G. Defensive Publication Dunn, Def.Pub. of Ser. No. 793,231, filed Oct. 5, 1966, published in 866 0.6.701on Sept. 16, 1969, Defensive Publication No. T866,0l4.

Primary Examiner-George T. Hall Att0rneySmyth, Roston & Pavitt ABSTRACTAn easy opening container wall including a main score line in thecontainer wall defining a panel removable therefrom and a tab connectedto the panel to initiate severance of the panel. A plurality ofgenerally radially extending secondary score lines are formed in thepanel and sections of the panel are preferably axially offset relativeto each other.

7 Claims, 5 Drawing Figures EASY OPENING CONTAINER WALL BACKGROUND OFTHE INVENTION An easy opening container wall typically includes acontainer wall of sheet material having a main score line thereindefining a panel removable therefrom and a tab to initiate severance ofthe panel from the container wall. Often times the panel is largerelative to the size of the container wall and it may cover a majorportion of, or substantially all of, the area of the container wall.

During transit the easy opening container is subjected to shock andvibration forces as a result of product movement within the container.Specifically the usual shocks encountered during transit causes theproduct to be repeatedly forced against the container wall.

The stress thus imparted to the container wall is not evenly distributedthroughout the container wall because of the irregular cross section ofthe container wall due to the weakening of the container wall by themain score line. Rather, the stress is concentrated at the main scoreline. This repeated stressing of the main score line is so substantialthat it can result in the rupture of the sheet material along the mainscore line, through fatigue or otherwise, with consequent spillageand/or spoilage of the product. In some instances the rupturing alongthe main score line will be assisted by a positive or negative pressurewithin the container.

SUMMARY OF THE INVENTION The present invention solves this problem byreducing the stressing of the container wall along the main score line.This is accomplished by distributing the stress more evenly throughoutthe container wall thereby reducing the stress which must be absorbed bythe sheet material along the main score line. Thus, the stressconcentration which existed heretofore along the main score line iseliminated.

To distribute the stress, the present invention teaches weakening of thepanel at selected regions so that the weakened regions will absorbgreater proportions of the stress than they would in an unweakenedstate. In this manner the stress is distributed to various regions ofthe panel withconsequent reduction in stress along the main score line.The weakened regions serve to protect the main score line.

The weakened regions are preferably in the form of generally radiallyextending secondary score lines. In a preferred form of the invention,the weakened regions are substantially evenly spaced circumferentiallyand extend from locations spaced outwardly of the center of the panel toterminate radially inwardly of the main score line. The weakened regionsand the main score line preferably do not intersect because intersectionof score lines in a panel can result in leakage of the product throughsuch intersection. However, the weakened regions preferably extend to alocation closely adjacent the main score line. By so doing the weakenedregions can absorb greater proportions of the stress to thereby givegreater protection to the main score line.

The formation of the secondary score lines causes flow of metal awayfrom or outwardly of the secondary score lines. This produces excessmetal in the regions of the panel adjacent the secondary score lines.The presence of excess metal renders the container wall bistable, i.e,,it produces a tendency of the container wall to oil can.

To avoid this problem, the present invention teaches axially offsettingsections of the panel. The offsetting of the sections of the panelcauses stretching of the panel to, in effect, use up at least some ofthe excess metal produced by the formation of the secondary score lines.

This can be advantageously accomplished by offsetting or stretching ofthe panel across the secondary score lines so that the stretching willoccur at regions where the excess metal exists. To use up the excessmetal adjacent the radial inward ends of the secondary score lines,another section of the panel inwardly of the secondary score lines ispreferably axially offset.

Because the offsetting of the panel is for the purpose of utilizing theexcess metal produced during the formation of the secondary score lines,the offsetting operation should not occur prior to the operation inwhich the secondary score lines are formed. Preferably, the offsettingof the panel occurs following the formation of the secondary scorelines. To avoid excessive weakening of the panel, the secondary scorelines should have a higher residual than the main score line. Of course,the shape, length, spacing, and depth of each of the secondary scorelines can be varied depending upon the results desired.

The invention, both as to its organization and method of operationtogether with further features and advantages thereof, may best beunderstood by reference to the following description taken in connectionwith the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an easy openingcontainer wall constructed in accordance with the teachings of thisinvention.

FIG. 2 is an enlarged fragmentary sectional view taken along line 2-2 ofFIG. 1.

FIG. 3 is an enlarged fragmentary sectional view similar to FIG. 2illustrating an initial operation in the method of making the easyopening container wall of FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view taken along line 4-4 ofFIG.-3.

FIG. 5 is an enlarged fragmentary sectional view taken on an axiallyextending plane through a portion of the easy opening container wallwhich has the main score line.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and inparticular to FIG. 1 thereof, reference numeral 11 designates an easyopening container wall constructed in accordance with the teachings ofthis invention. The easy opening container wall 11 includes a containerwall 13 in the form of a can end constructed of sheet material such asan aluminum alloy and having a peripheral attaching flange 15 to securethe container wall to a can body (not shown). A line of weakness in theform of a main score line 17 is formed in the container wall 13 anddefines a tear portion or panel 19 which covers a substantial area ofthe container wall 13. Although the main score line 17 and the panel 19may assume various configurations and sizes, in the embodimentillustrated they are circular in plan and the panel 19 coverssubstantially all of the area in plan of the container wall 13.

A tab 21 is attached to the panel 19 by suitable means such as a rivet23. The tab 21 constitutes means for manually removing the panel 19 fromthe container wall 13, and although a specific form of tab has beenillustrated, it should be understood that various other kinds of tabssuitable for removing the panel 19 may be utilized.

In the embodiment illustrated,the tab 21 includes a sub stantiallylongitudinally rigid lever portion 25 through which the rivet 23projects to attach the tab to the panel 19. The lever portion 25includes a rupturing nose 27 which preferably overlies a region of thescore line 17 and which can be forced thereagainst to initiate severanceof the panel 19 from the container wall 13. Specifically, the'score line17 is ruptured by the rupturing nose 27 which forces a portion of thepanel .17 inwardly.

The tab 21 also includes a handle portion 29 integrally joined to thelever portion 25 by apliable connection portion 31. The tab 21 canadvantageously be integrally constructed from a single piece of sheetmaterial such as an aluminum al- To remove the panel 19, the user graspsthe radial outer end of the handle portion 29 and moves the latterupwardly, i.e., away from the panel 19. Such upward movement ofthe outerend of the handle portion 29 can easily be accomplished because theconnecting portion 31 is readily bendable. When the handle portion 29has been elevated above the panel 19 at an appropriate angle, the usercan firmly grasp the handle portion and exert an outward pulling forcewith the result that the end of the lever portion 25 remote from therupture nose 27 is elevated. This causes the lever portion 25 to pivotwith the result that the rupturing nose 27 is forced against the panel19 with sufficient force to sever the sheet material of the containerwall 13 along the score line 17. Then, by exerting a pulling force inthe appropriate direction, the entire panel 19 may be removed from thecontainer wall 13.

The panel 19 also includes a plurality of radially extending secondaryscore lines 33. The score lines 33 weaken the panel 19 inwardly of themain score line 17. Although the particular configuration of the scorelines 33 can be varied, in the embodiment illustrated the secondaryscore lines are linear and extend along radial lines. To obtain the beststress distribution, the secondary score lines 33 are preferablysubstantially equally spaced circumferentially and preferably extend tolocations closely adjacent the main score line 17. The number ofsecondary score lines 33 can be varied depending upon the resultsdesired and the particular number shown in FIG. 1 should not beconsidered limiting.

The panel 19 has an inner section 35, an intermediate section 37, and anouter section 39 with the inner and intermediate sections beingintegrally connected by a connecting section or wall 41 and with theintermediate and outer sections being integrally connected by aconnecting section or wall 43. In the embodiment illustrated, the innersection 35 is circular and the intermediate section 37 and the outersection 39 are both annular. Each of the secondary score lines 33preferably extends from a location slightly radially outwardly of theconnecting section 41 across major portions of the sections 37, 43 and39 to terminate at locations closely adjacent and spaced radiallyinwardly of the main score line 17. Each of the secondary score lines 33defines a secondary residual web 45 (FIGS. 2 and 4) and the main scoreline 17 defines a main residual web 46 (FIG. 5). The residual web 45 ispreferably thicker than the residual web 46.

With the container wall 13 scored as shown in FIG. 1, the secondaryscore lines 33 constitute weakened regions and the zone of the sheetmaterial between adjacent secondary score lines constitute panelsegments integrallyjoined at least in part by the sheet material alongthe secondary score lines. In use of the easy opening container wall 11,the product (now shown) contained within the container body (not shown)to which the easy opening container wall 11 is attached will move duringtransit of the container. Such movement of the product within thecontainer inevitably results in the application of repeated forces tothe panel 19. If the secondary score lines 33 were not provided, thesheet material along the main score line would be substantially repeatedstressed by such movement of the product. However, due to the weakeningof the panel 17 by the secondary score lines 33, the panel has numerousregions other than the main score line 17 which can resiliently flex toabsorb some of the force applied against the panel 19. Thus, thesecondary score lines 33 cause a more even distribution of the stressthroughout the panel 19 than would be obtained if the score lines werenot provided.

An early operation in the making of the easy opening container wall 11is illustrated in FIG. 3. First, the container wall I3 is scored to formthe main score line 17 and the secondary score lines 33 as shown in FIG.3. These scoring operations may be carried out simultaneously orsequentially with either the main score line or the secondary scorelines being first formed. During the scoring of the secondary scorelines 33, metal is displaced outwardly from each of the score lines 33in all directions. This causes the presence of excess metal in a zonewhich completely surrounds each of the secondary score lines 33.

Because of the relatively large number of the secondary score lines 33,if this excess metal condition were allowed to remain, the containerwall 13 would be bistable. The present invention eliminates the bistablecondition of the container wall 13 by axially offsetting the sections35, 37 and 39 of the panel 19, i.e., by panel forming. As shown in FIG.2, the intermediate section 37 is offset axially inwardly from the outersection 39 and the inner section 35 is offset axially inwardly from theintermediate section 37. This axial offsetting of the panel sections 35,37 and 39 stretches the metal along and adjacent the connecting sections41 and 43.

This stretching which occurs during the panel forming operation removesat least some of the excess metal from the zone surrounding thesecondary score lines 33. For this reason, the connecting section 43preferably extends generally through a central region of each of thesecondary score lines 33 so that it can be most effective in drawing orutilizing the excess metal produced in the panel 17 by the formation ofthe secondary score lines. The connecting section 41 is located slightlyradially inwardly of the inner radial end of the score lines 33 so thatit can use the excess metal which is adjacent and between the inner endsof the secondary score lines. Of course, variation in the location andnumber of the connecting sections can be varied, and the configurationillustrated should be considered exemplary of a preferred manner ofremoving the excess metal.

Because panel forming utilizes excess metal formed during the scoring ofthe secondary score lines, the panel forming operation should occursimultaneously with, or subsequent to, the secondary scoring operation.However, to score and panel form simultaneously would present difficulttooling design problems and for this reason it is preferred to panelform after the secondary scoring operation.

Although an exemplary embodiment of the invention has been shown anddescribed, many changes, modifications and substitutions may be made byone having ordinary skill in the art without necessarily departing fromthe spirit and scope of this invention.

What is claimed is:

1. In an easy opening container wall wherein a line of weakness isformed in a container wall to define a panel at least partiallyremovable from the container wall and a tab is connected to thecontainer wall to initiate severance of the panel from the containerwall and wherein the container wall is subjected to a force prior tomanipulation of the tab which stresses the line of weakness, theimprovement to reduce the amount of stress which will be absorbed by thecontainer wall at the line of weakness in response to the application ofthe force to the container wall comprising:

the panel being weakened at selected regions thereof with the weakenedregions of said panel absorbing some of the stress resulting from saidforce to thereby reduce the amount of stress which is absorbed by saidline of weakness, said panel being nonrupturable at said selectedregions by manipulation of the tab, said panel including first andsecond panel sections offset axially from each other and at least one ofthe weakened regions lies partially in both of said sections.

2. In an easy opening container wall wherein a main line of weakness isformed in a container wall to define a panel at least partiallyremovable from the container wall and a tab is connected to thecontainer wall to initiate severance of the panel from the containerwall, the improvement comprising:

a plurality of secondary lines of weakness in said panel, said panelbeing nonrupturable along said secondary lines of weakness in responseto manipulation of the tab to sever the main line of weakness; and

each of said secondary lines of weakness beginning at a location spacedfrom the center of said panel and extending generally radially outwardlytoward the main line of weakness to terminate in spaced relationship tosaid main line of weakness, said panel including first and secondaxially offset sections with at least one of said secondary lines ofweakness extending at least part way across both of said sections.

3. In an easy opening container wall wherein a main line of weakness isformed in a container wall to define a panel at least partiallyremovable from the container wall and a tab is connected to thecontainer wall to initiate severance of the panel from the containerwall, the improvement comprising:

a plurality of secondary lines of weakness in said panel, said panelbeing nonrupturable along said secondary lines of weakness in responseto manipulation of the tab to sever the main line of weakness; and

said panel including inner, outer and intermediate sections with saidintermediate section substantially circumscribing said inner section andwith said outer section substantially circumscribing said intermediatesection said sections being axially offset from each other, saidsecondary score lines extending substantially across said outer andintermediate sections.

4. An easy opening container wall comprising:

a container wall of sheet material having a main score line thereindefining a main residual web, said main residual web defining a panel atleast partially removable from the container wall, said panel covering amajor portion of said container wall;

a tab attached to said panel to initiate removal of said panel from saidcontainer wall by rupturing said residual web;

said panel having a plurality of secondary score lines therein, each ofsaid secondary score lines defining a secondary residual web of greaterthickness than said main residual web; and

said panel having an inner section, each of said secondary score linesextending generally radially from a location closely adjacent said innersection to a location closely adjacent the main score line, saidsecondary score lines being substantially equally spacedcircumferentially.

5. An improvement as defined in claim 3 wherein said secondary lines ofweakness extend generally radially of the panel.

6. An improvement as defined in claim 5 wherein each of said secondarylines of weakness terminates short of said main line of weakness, saidsecondary lines of weakness being spaced circumferentially of the panel.

7. An improvement as defined in claim 2 wherein the main line ofweakness defines a main rupturable web and each of the secondary linesof weakness defines a secondary rupturable web, a major portion of themain rupturable web being thinner than major portions of a majority ofthe secondary rupturable webs.

1. In an easy opening container wall wherein a line of weakness isformed in a container wall to define a panel at least partiallyremovable from the container wall and a tab is connected to thecontainer wall to initiate severance of the panel from the containerwall and wherein the container wall is subjected to a force prior tomanipulation of the tab which stresses the line of weakness, theimprovement to reduce the amount of stress which will be absorbed by thecontainer wall at the line of weakness in response to the application ofthe force to the container wall comprising: the panel being weakened atselected regions thereof with the weakened regions of said panelabsorbing some of the stress resulting from said force to thereby reducethe amount of stress which is absorbed by said line of weakness, Saidpanel being nonrupturable at said selected regions by manipulation ofthe tab, said panel including first and second panel sections offsetaxially from each other and at least one of the weakened regions liespartially in both of said sections.
 2. In an easy opening container wallwherein a main line of weakness is formed in a container wall to definea panel at least partially removable from the container wall and a tabis connected to the container wall to initiate severance of the panelfrom the container wall, the improvement comprising: a plurality ofsecondary lines of weakness in said panel, said panel beingnonrupturable along said secondary lines of weakness in response tomanipulation of the tab to sever the main line of weakness; and each ofsaid secondary lines of weakness beginning at a location spaced from thecenter of said panel and extending generally radially outwardly towardthe main line of weakness to terminate in spaced relationship to saidmain line of weakness, said panel including first and second axiallyoffset sections with at least one of said secondary lines of weaknessextending at least part way across both of said sections.
 3. In an easyopening container wall wherein a main line of weakness is formed in acontainer wall to define a panel at least partially removable from thecontainer wall and a tab is connected to the container wall to initiateseverance of the panel from the container wall, the improvementcomprising: a plurality of secondary lines of weakness in said panel,said panel being nonrupturable along said secondary lines of weakness inresponse to manipulation of the tab to sever the main line of weakness;and said panel including inner, outer and intermediate sections withsaid intermediate section substantially circumscribing said innersection and with said outer section substantially circumscribing saidintermediate section said sections being axially offset from each other,said secondary score lines extending substantially across said outer andintermediate sections.
 4. An easy opening container wall comprising: acontainer wall of sheet material having a main score line thereindefining a main residual web, said main residual web defining a panel atleast partially removable from the container wall, said panel covering amajor portion of said container wall; a tab attached to said panel toinitiate removal of said panel from said container wall by rupturingsaid residual web; said panel having a plurality of secondary scorelines therein, each of said secondary score lines defining a secondaryresidual web of greater thickness than said main residual web; and saidpanel having an inner section, each of said secondary score linesextending generally radially from a location closely adjacent said innersection to a location closely adjacent the main score line, saidsecondary score lines being substantially equally spacedcircumferentially.
 5. An improvement as defined in claim 3 wherein saidsecondary lines of weakness extend generally radially of the panel. 6.An improvement as defined in claim 5 wherein each of said secondarylines of weakness terminates short of said main line of weakness, saidsecondary lines of weakness being spaced circumferentially of the panel.7. An improvement as defined in claim 2 wherein the main line ofweakness defines a main rupturable web and each of the secondary linesof weakness defines a secondary rupturable web, a major portion of themain rupturable web being thinner than major portions of a majority ofthe secondary rupturable webs.